1. Field of the Invention
The present invention relates to a laminated ceramic electronic component and a method for manufacturing the same, and more particularly, to a laminated ceramic electronic component such as a resonator, a filter, an inductor, a delay line, a coupler or the like having a pattern electrode such as an inner conductor and a method for manufacturing the same.
2. Description of the Prior Art
FIG. 19 is an exploded front view showing an example of a conventional resonator which is in the background of the present invention, and FIG. 20 is a sectional illustrative view showing an essential portion thereof. The resonator 1 shown in FIG. 19 and FIG. 20 includes a first dielectric layer 2a. A band-shaped inner conductor 3 as a pattern electrode is formed on one main surface of the first dielectric layer 2a. Furthermore, a second dielectric layer 2b is formed on one main surface of the first dielectric layer 2a so as to cover the inner conductor 3. A first earth electrode 4a is formed on the second dielectric layer 2b so as to oppose the inner conductor 3. Also, a second earth electrode 4b is formed on the other main surface of the first dielectric layer 2a so as to oppose the inner conductor 3. Furthermore, a third dielectric layer 2c is formed on the other main surface of the first dielectric layer 2a so as to cover the second earth electrode 4b. Thus, a strip line is formed of the first and the second dielectric layers 2a and 2b, the inner conductor 3, and the first and the second earth electrodes 4a and 4b.
Conductive paste to form the inner conductor is printed on one main surface of a first ceramic green sheet so as to form a thick film thereon Conductive paste to form each of the earth electrodes is printed on each one main surface of second and third ceramic green sheets so as to form a thick film thereon. Then, the second and the third ceramic green sheets are laminated on both main surfaces of the first ceramic green sheet, these ceramic green sheets and so on are bonded by pressing, sintered and so on, thereby the resonator 1 shown in FIG. 19 and FIG. 20 is formed.
FIG. 21 is a perspective view showing an example of a conventional filter which is in the background of the present invention, and FIG. 22 is an exploded perspective view thereof. The filter 10 includes a first dielectric layer 11a. Two band-shaped inner conductors 12a and 12b as pattern electrodes are formed in parallel with each other at an interval on one main surface of the first dielectric layer 11a. The inner conductors 12a and 12b are electromagnetically coupled with each other. Furthermore, a second dielectric layer 11b is formed on one main surface of the first dielectric layer 11a so as to cover the inner conductors 12a and 12b. Two capacitor electrodes 13a and 13b are formed on the second dielectric layer 11b. Furthermore, a third dielectric layer 11c is formed on the second dielectric layer 11b so as to cover the capacitor electrodes 13a and 13b. Two capacitor electrodes 13c and 13d are formed on the third dielectric layer 11c so as to oppose the two capacitor electrodes 13a and 13b. Furthermore, a fourth dielectric layer 11d is formed on the third dielectric layer 11c so as to cover the capacitor electrodes 13c and 13d. A first earth electrode 14a is formed on the fourth dielectric layer 11d. Also, two capacitor electrodes 13e and 13f are formed on the other main surface of the first dielectric layer 11a. Furthermore, a fifth dielectric layer 11e is formed on the other main surface of the first dielectric layer 11a so as to cover the capacitor electrodes 13e and 13f. A second earth electrode 14b is formed under the fifth dielectric layer 11e so as to oppose the two capacitor electrodes 13e and 13f. Furthermore, a sixth dielectric layer 11f is formed under the fifth dielectric layer 11e so as to cover the second earth electrode 14b.
Six outer electrodes 15a through 15f are formed on side surfaces of the first through the sixth dielectric layers 11a through 11f. The outer electrodes 15a and 15d are connected with the capacitor electrodes 13c and 13d, respectively. The outer electrodes 15a and 15d are used as input/output terminals. The outer electrode 15b is connected with one end of the inner conductor 12a and the capacitor electrodes 13a and 13e. The outer electrode 15c is connected with one end of the inner conductor 12b and the capacitor electrodes 13b and 13f. The outer electrodes 15e and 15f are connected with the first and the second earth electrodes 14a and 14b. The outer electrodes 15e and 15f are used as earth terminals.
Thus, in the filter 10 shown in FIG. 21 and FIG. 22, a resonator consisting of a strip line is formed of the first through the fifth dielectric layers 11a through 11e, the inner conductor 12a, and the first and the second earth electrodes 14a and 14b, and another resonator consisting of another strip line is formed of the first through fifth dielectric layers 11a through 11e, the inner conductor 12b, and the first and the second earth electrodes 14a and 14b. In this case, since the inner conductors 12a and 12b are electromagnetically coupled with each other, the two resonators are also electromagnetically coupled with each other. Furthermore, in the filter 10, each capacitor is formed between the capacitor electrodes 13a and 13c, between the capacitor electrodes 13b and 13d, between the capacitor electrode 13e and the second earth electrode 14b, and between the capacitor electrode 13f and the second earth electrode 14b. Accordingly, the filter 10 has an equivalent circuit shown in FIG. 23.
Conductive paste to form the inner conductors is printed on one main surface of a ceramic green sheet so as to form a thick film thereon. Conductive paste to form the capacitor electrodes is printed on each one main surface of the other ceramic green sheets so as to form a thick film thereon. Furthermore, conductive paste to form the earth electrodes is printed on each one main surface of the other ceramic green sheets so as to form a thick film thereon. Then, these ceramic green sheets and so on are laminated, bonded by pressing, sintered and so on, thereby the filter 10 shown in FIG. 21 and FIG. 22 is formed.
However, in the resonator 1 shown in FIG. 19 and FIG. 20, since the inner conductor 3 is formed by printing conductive paste so as to form a thick film, the thickness t (shown in FIG. 20) of the inner conductor 3 is as small as about 10 .mu.m. Therefore, in the resonator 1, the resistance component and the ohmic loss of the inner conductor 3 as a pattern electrode are large, and Q is small.
Similarly, in the filter 10 shown in FIG. 21 and FIG. 22, since the inner conductors 12a and 12b are formed by printing conductive paste so as to form a thick film, each thickness of the inner conductors 12a and 12b is as small as about 10 .mu.m. Therefore, in the filter 10, each resistance component and each ohmic loss of the inner conductors as pattern electrodes are large, each Q of the resonators is small, and the insertion loss is large.